I had a conference call with some people in one of our facilities in China.  My manager is currently over there and I was going to run a presentation and demo from over here.  I VPN'ed in from home and waited for the call to begin.  Evidently, the conference room they were in had a broken telephone, so they were unable to call in.  After a while of trying to fix it, my manager said he didn't think they were going to get it working and did I have any ideas.  We were already communicating via Google Talk, so I just hit the "call" button.  A couple of rings later, we had a perfectly clear and relatively delay-free voice communication channel.

I was running the demo via netmeeting, but the netmeeting voice chat is horrible quality and there is a sizeable delay.  I was able to give the whole presentation and demo via Google Talk.  Well, until someone kicked the network cable on the other end and disconnected the whole thing.